A driver's lack of awareness of people or vehicles approaching a merger or intersection can result in collisions. In many instances, a driver's awareness is limited due to an inability to see an object until it becomes a hazard. For example, a driver's view of a vehicle approaching an intersection may be blocked by an object, such as a building. The approaching vehicle may appear in the driver's view only at or very near the intersection, leaving little time for the driver to recognize the danger and react. In general, the lack of visibility of occluded objects is a factor that contributes to many collisions.